Re: Apple IIpluse motherboard getting closer

[mjmahon@aol.com (Michael J. Mahon)]

Vince Briel wrote:

>> You are getting closer.
>> Type <RETURN>, then "TEXT", then <RETURN>. If this works, your graphics
>> mode selection logic does not initialize properly. If not, this logic is
>> gone. Now you can start swapping 74LSxx (or pulling them from their
>> sockets and reseating them)
>> 
>> 
>> Patrick
>
>
>[return] text [return]  didn't work, still block characters.  I will now
>start swapping chips.  Any specific ones I should try?

Another possibility is that the text ROM or the text shift register
are not working.  The "block graphics" may not be lo-res graphics
at all, but rather a stuck video data pattern.

The text ROM is at A5, and the 74166 text shift register is at A3.
Check contacts, orientation in socket, and IC functionality (by
swapping with known good ICs).

-michael

 Email:  mjmahon@aol.com
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